1. Field of the Invention
This invention relates to disposable wiper products useful for a wide variety of industrial and consumer applications including those in the automotive, food services, and electrical industries as well as for general purpose household wiping. Such wipers must be low cost and yet provide the strength, absorbency, cloth-like character and other properties desirable for such wiping applications. Nonwoven fabrics, in general, have received wide acceptance as nonwoven disposable wipers both for specific applications and general purpose wiping. For many such applications nonwoven wipers can out-perform traditional cloth and paper wiping products. However, for some applications, it is desired to even further improve certain nonwoven wiper properties such as resistance to linting and streaking, and it is generally desirable to increase wiper absorbency and strength.
2. Description of the Prior Art
U.S. Pat. No. 4,307,143 to Meitner issued Dec. 22, 1981 describes meltblown microfiber wipers treated with a surfactant and embossed. Such wipers are demonstrated to have improved absorbency and wiping properties when compared with traditional wiper materials. U.S. Pat. No. 4,298,649 to Meitner dated Nov. 3, 1981 describes a multi-component nonwoven wiper having a layer of meltblown microfibers combined with a split film or fibrillated foam layer. This wiper exhibits low metal chip pick-up characteristics of particular interest in the automotive finishing application. This property is obtained without significant deterioration in wiping properties. U.S. Pat. No. 4,328,279 to Meitner and Englebert dated May 4, 1982 relates to a meltblown nonwoven wiper treated with certain surfactants to result in low sodium content of particular interest in electronics industry wiping application. U.S. Pat. No. 4,041,203 to Brock and Meitner dated Aug. 9, 1977 relates to nonwoven fabrics and sterile wrapper materials made by combining layers of meltblown thermoplastic fibers with one or more continuous thermoplastic filament layers. The disclosure recognizes that such materials can be treated for absorbency and used in wiper applications. U.S. Pat. No. 4,196,245 to Kitson, Gilbert, Jr., and Israel dated Apr. 1, 1980 relates to a composite nonwoven fabric useful in disposable surgical items and which can comprise one or more meltblown layers loosely bonded to one or more spunbounded layers.
The preparation of polyolefin microfiber webs is known and described, for example, in Wendt, Industrial and Engineering Chemistry, Vol. 48, No. 8 (1956) pages 1342 through 1346 as well as in U.S. Pat. Nos. 3,978,185 to Buntin et al issued Aug. 31, 1976, 3,795,571 to Prentice, issued Mar. 5, 1974, and 3,811,957 to Buntin issued May 21, 1974. The Buntin et al patent further discloses that mats of meltblown polyolefins are useful in wiping cloths and hydrocarbon absorption material.
Production of substantially continuous filaments is also known, and illustrative techniques are set forth in U.S. Pat. Nos. Kinney 3,338,992 and 3,341,394, Levy 3,276,944, Peterson 3,502,538, Hartmann 3,502,763 and 3,509,009, Dobo 3,542,615 and Harmon Canadian Pat. No. 803,714. Reference may also be had to the above identified Brock and Meitner U.S. Pat. No. 4,041,203 for methods of producing combinations of meltblown thermoplastic fibers and continuous filament thermoplastic fibers. Commonly assigned U.S. patent application Ser. No. 146,450 to Appel and Morman, now U.S. Pat. No. 4,340,563 dated July 20, 1982, describes an alternative method for producing continuous filament thermoplastic webs.